I haven't been able to find much on the numbers 1 and 3 (not too sure of the latter either) but here's some additional info regarding sample 2:

The beautiful, slow-growing camel thorn grows well in poor soils and in harsh environmental conditions. It is an ideal shrub/tree for a small or large garden. This is a protected tree in South Africa

DescriptionThe camel thorn ranges from a 2 m spiny shrub to a 16 m robust tree. The stem is shiny reddish brown when young. The bark of a mature tree is grey to blackish brown and is deeply furrowed; bearing pairs of almost straight, whitish or brown spines. Spines often have swollen bases and appear at the bases of the leaves. The fully developed spines may be up to 60 mm long. The leaves are twice divided. There are normally 2 to 5 pairs of pinnae per leaf and 8 to 18 pairs of leaflets (pinnules) per pinna. They are hairless and have a prominent underside vein on the undersurface.
The tree bears bright yellow ball-like flowers that are sweetly scented. They are borne in late winter and last through to summer.
The fruit is variable and ranges from small and almost cylindrical to typically large, flat, thick, semicircular or half-moon-shaped pods. They are up to 130 mm long and 50 mm wide and are covered by velvety grey hairs. They are semi-woody, but spongy inside; the pods do not open even when ripe but fall to the ground in winter. Seeds are thick, robust and lens-shaped.

DistributionThis species is widely distributed inland, from the Northern Cape through to Limpopo Province. It also extends to Namibia, Botswana, Zimbabwe and to central Africa.

Name DerivationsAcacia is a very large genus of shrubs and trees coming from occurring all over the tropical world. The largest number of species in this genus is found in Australia where they have in the region of 900 species. The name Acacia comes from the Greek word for thorns, since a large number of species are thorny.
Acacia belongs to the mimosa family. This is the third largest woody plant family comprising about 100 tree species in South Africa . The other common member of this family is Albizia which is easily distinguished from Acacia in that the plants have no thorns. Both Acacia and Albizia are important ecological components throughout bushveld areas of the country.
Recent taxonomic developments in the genus Acacia indicate that the name Acacia as it pertains to Africa will soon change to give recognition to the differences between the Australian acacias and the African acacias. The African acacias will more than likely be divided into two separate genera, Vachalia and Senegalia, whereas the Australian members will retain the name Acacia.

EcologyThe camel thorn is a competitive species that can displace preferred vegetation. It has been assessed as potentially very highly invasive in Australia : climate predictions indicate that it could occupy large inland areas of northern Australia if allowed to spread.
This is a relict of the parental stock of African Acacia species and is one of the major trees, and frequently the only sizeable tree of the deserts of southern Africa . It is a long-lived plant that grows on sand in areas with an annual rainfall of less than 40 mm to 900 mm, and tolerates hot summer temperatures and severe frosts. In very dry areas Acacia erioloba occurs along watercourses or where underground water is present. The taproot can descend to 60 m, providing access to deep ground water.

UsesThe pods are useful fodder for cattle and are favoured by wild animals in Africa , especially elephants who chew the pods and disperse the seed in their dung. The timber is strong and is highly prized for firewood.
Dry powdered pods can be used to treat ear infections. The gum can be used for the treatment of gonorrhoea and the pulverized, burned bark can be used to treat headaches. The root can be used to treat toothache. To treat tuberculosis, the root is boiled for a few minutes and the infusion is swirled around in the mouth and spat out.
It is believed that lightning will strike at the Acacia erioloba more readily than other trees. The seeds can be roasted and used as a substitute for coffee; the gum is also eaten by humans as well as animals. The root bark is used by the Bushmen to make quivers. Many wild animals love to eat the pods and will rest in the dense shade, in the heat of the African sun.
Source

1)Acacia erioloba x A. haematoxylon (hybrid), False camel thorn, basterkameeldoring In some places, hybrids between the Camel thorn and the Grey Camel thorn are found. The growth form is similar to the Camel thorn but the foliage is greyer and sparser with small and closely packed leaflets. It has yellow flowers (late spring to early summer). The pods are an intermediate between 2 others and also the same velvety grey.

The Camel thorn is a keystone species in the Kalahari, a keystone species being defined as a species upon which many other plant and animals species depend.
The life cycle of many mammals, birds and insects are intimately bound up with these trees as they often provide the primary source of food and shelter. Distinctive plant assemblages often develop beneath the canopy of these trees as a result of nutrient concentration and soil disturbance by animals.

Wilted green pods are high in prussic acid and a very poisonous substance that can kill livestock.
Pods are also used to make porridge.

(not Sanparks orientated but it is said that cows feeding on these pods shows a noticeable increase in milk production)

The gum is one of the favourite foods of the Kori bustard and from a human point if view an infusion made from the gum is taken for coughs, colds and tuberculosis.

3) Acacia haematoxylon Grey camel thorn, VaalkameeldoringAnd Bouf has given us some info on that